1. Field of the Invention
This invention relates generally to semiconductor device fabrication and to thin film interconnection module fabrication, and more particularly to a method and apparatus for selectively disconnecting predetermined areas on these devices, including areas below the surface of the device.
2. Description of the Prior Art
In present semiconductor device fabrication technology, it is often necessary to utilize redundancy in order to improve fabrication yields as device density increases. In such semiconductor chips, redundant devices are fabricated, and if a device or a portion of a chip is nonfunctional, a laser beam is used to cut the conductors on the surface of the semiconductor chip leading to the nonfunctional portion in order to isolate that portion from the properly functioning devices. This technique is called laser ablation and is now commonly used by semiconductor chip manufacturers when manufacturing large scale devices, such as, for example, 256K memory devices; however, the technique is usable only for breaking connections on the surface of a device and cannot be used to break connections below the surface without causing damage to the surrounding area.